Valve



Oct. 5, 1948.

J. w. MARSH VALVE Filed May 30, 1945 1 Patented Oct. 5, 1948 lUNI'I'ED STATES EATFENT oFFlcE This invention relates to new and useful improvements in valves, and has lfor an object the provision of a valve which will maintain any desired pressure on the discharge side. Another object of the invention is the provision of a valve having a large orifice for the rapid accumulation of pressure on the discharge side with prompt and positive 'closure when desired pressure is reached. A further object of the invention is to provide a valve having accurate control of released pressure without manipulation of the control handle between discharge and lap positions. Yet another object o-f this invention is to provide a valve structure of the type described which is provided with poppet valves `which are substantially balanced for accurate control. A still further object of the invention is to provide a pressure control valve which is simple and easy to construct and requires a minimum of maintenance. Still another object of the invention is to provide a fluid pressure system embodying as a part thereof a novel vvalve of the type just described.

A valve embodying the present invention may be used in all cases rwherein it is desired to'mainparticularly adaptable for the control of trainline pressure in an air-'brake system. The valve commonly used for this purpose' consists of a rotatable disc on a flat seat, the disc and seat ybeing provided with ports. Provision is made for registration of ports communicating with a source of fluid pressure and the train line, as well as with an equalizing chamber, tocharge the train line and the equalizing chamber. Other ports provide communication between a sourcei'f55 of fluid pressure and a pressure-reducing valve, and between the pressure-reducing valve and the train line and the equalizing chamber to maintain operating pressure in the train line and the equalizing chamber. munication between the equalizing chamber and the atmosphere to reduce pressure in the equalizing chamber. Yet other lports provide communication between the train line and the atmosphere for emergency brake applications. Service reductions in train-line pressure are attained by reducing pressure in the equalizing chamber above an equalizing piston, the underside of which is subject to train-line pressure. Train-line pressure then raises the equalizing piston which opens a valve venting the train line to atmosphere until the vpressure under Vthe equalizing piston is reduced sufficiently to permit the reduced equalizing chamber pressure'tomove the equalizing piston down and close the venting valve. It is Valso tain a predetermined fluid pressure, and it is Other ports provide com-" V2 a common practice to provide a lap position oi the valve to -close all ports and hold pressures attained.

It will be observed that the presently used valving system only charges or releases p-ressure from a system just as ythe manual opening or closing of a plurality oi valves having similar communications would do. No provision is made for the maintenance of a predetermined uid pressure without Vfurther attention on the part of the operator. :Fluid pressure in a communicating or utilizing means may be decreased or increased, such as .by movement o-f a piston in the utilizing means, by leakage, or -by the eiect of temperature changes, condensation or evaporation. The preslent invention compensates for any changes in a predetermined fluid pressure, and automatically maintains suchpressure on the discharge side o'f the valve, corresponding to the valve setting.

Since the valve of the present invention will Yautomatically maintain a predetermined pressure on the discharge side, the entire operation .of-an air-brake system becomes greatly simplied. It may be ytaught to a beginner in a much shorter time than kis now required, and the operation of the entire system is more positive and under better over-all control. It also eliminates the need for an equalizing reservoir and-a feed valve.

A valve embodying the principles of the present invention, while v.extremely useful in air-brake applications, Iwill have a large variety of other uses as well, all as will lbe appreciated by tho-se skilled in the art.

VIn the drawing: l

Fig. -1 is a vertical section taken through a valve embodying the present invention.

Fig. 2 is a horizontal section taken on line 2--2 of Fig. l.

The self lapping automatic brake valve utilizing a floating seat principle, and combining the `functions of the conventional automatic brake valve, equalizing reservoir, and lfeed valve, is i1-` lustrated in Figs. 1 and 2. This valve includes a vhousing which may be formed in a plurality of sections Il), H, l2 and I3. -By forming the housing inthis fashion, the valve is readily assembled, the sections having aligned apertures I4 in the several corner sections l5 which receive bolts (not shown) for assembly. -Chamberl communicates with port 2U, which may be considered as the outlet port, leading to the train line, and control chamber 2l communicates with exhaust port 2.2 leading to the external atmosphere in a manner later tc be described. The housing further includes port 23, which may be considered as the inlet port, connecting the main reservoir with chamber 24.

At 26 there is illustrated a double-seated valve comprising lower valve portion 21 seated at 28, which is a fixed seat, and an upper valve portion 29 which is seated at 30, which is a floating seat associated with a lpressure actuated member, such as a piston 3| which moves in a lpiston chamber 33 formed intermediate the upper and lower ends of upper housing section I3. Valve 26 is mounted for reciprocating movement in Valve support 32 formed in upper housing section |3. This valve structure is formed with a recess 34 to permit air to pass from chamber 24 connected rwith the main reservoir to chamber 2| when lower valve portion 21 is open. A relatively heavy spring 38 urges piston 3| downwardly, thus closing valve portion 29. Pressure of spring 38 is controlled by a handle 39 which operates a sharppitched screw 40, the handle being keyed to the screw by any suitable means, such as by pin 43. A spring cap 4I engages the upper end of spring 38, and a ball 42 may be positioned between the spring cap and screw 46. The ball provides a friction-free seat. It takes up any cooking of the spring, and centers the load on the spring in order to permit the spring to float freely so as to avoid cocking the piston. When upper valve portion 29 is open, air in chamber 2| may be vented through seat 30, through port 212, and to the eX- ternal atmosphere.

A fluid pressure actuated member, such as a piston 46 mounted in piston chamber 4'I is subject on its lower surface to pressure in chamber 2|. Piston 46 forms a floating seat 48 for lower valve portion 49 of a double-seated valve 50. The upper valve portion I of this double-seated valve is seated at 52, which is a ilxed seat. Valve 50, which may be similar in construction to valve 26, is mounted for reciprocating movement in Valve support 53. With handle 39 in running position, i. e., the full normal tension of spring 38 urging piston 3| downwardly to the position of Fig. l, valves 21-29 are closed. The spring is so tensioned as to close seats 28 and 30 when normal train-line pressure exists in chamber 2|.

Any pressure in chamber 2| in excess of pressure in train-line chamber I9, due to reduction in train-line pressure, raises piston 46, closing valve 49 and opening valve 5I, thereby admitting main reservoir air directly to the train line. When the train-line pressure equalizes with the controlled pressure in chamber 2|, piston 46 moves downwardly to close valve 5I. This valve permits full flow of main reservoir air to the train line for rapid charging of the brake system right up to equalization pressure. The train line could, of course, be charged direct from chamber 2|, but as the train-line pressure approached control pressure, valve 21 would close gradually, extending the time of charging and causing excessive wear on the seat by wire drawing. When pressure is reduced in chamber 2| by opening handle 39, piston 46 is pushed down by the excessive train-line pressure, exhausting train-line air through valve 49 to chamber 2| and out through valve 29 and port 22. A restricted port 54 may be provided in piston 46, forming means for communication between chambers I9 and 2|. Port 54 may be of appropriate size to maintain train-line pressure against normal leakage, and to maintain equalization of .pressure between chambers I9 and 2 I, except when a substantial pressure change is effected in chamber 2| by operation of handle 39. The effect 0l restricted port 54 is to prevent too violent action of piston 46 which may result in undesirable pressure waves in the train line which communicates with chamber I9. Relatively small spring 59 which urges valve member 5U upwardly, and small spring 56 which urges valve member 26 downwardly, serve to balance the main reservoir pressure on valves 26 and 5|).

The admission or discharge of fluid from chamber I9 to increase or decrease fluid pressure in chamber I9 is effected by movement of piston 46, the upper surface of which is subjected to fluid .pressure in chamber I9. The lower surface of piston 46 is subjected to fluid pressure in chamber 2|, and an increase of iluid pressure in chamber 2| and below piston 46, over the iluid pressure in chamber I9, will move piston 46 upwardly, closing valve 49 and opening valve 5|, thereby admitting fluid from chamber 24 to chamber I9 until fluid pressure in chamber I9 and above piston 46 overcomes the fluid pressure in chamber 2| and below piston 46, whereupon piston 46 is forced downwardly, permitting valve 5I to close.

The self -lapping valve of the present invention automatically keeps train-line pressure equal to spring pressure. When the downward pressure on piston 3| exceeds the fluid pressure in chamber 2|, which latter pressure acts on the lower surface of piston 3|, piston 3| is forced downwardly, opening valve 2'I and permitting fluid to flow from chamber 24 to chamber 2|. This flow continues until fluid pressure in chamber 2| and below piston 3| is sufiicient to raise piston 3| against downward pressure of spring 38 until valve 21 is closed. Similarly, when the downward spring pressure on piston 3| is less than the fluid pressure in charnber 2| which acts on the lower surface of piston 3|, piston 3| is forced upwardly and away from valve 29, thereby permitting lluid to flow from chamber 2|, past valve seat 30, and to escape through port 22.

A reduction of fluid pressure in chamber 2| and below piston 46, below the fluid pressure in chamber I9, will move piston 46 downwardly, opening valve 49 and permitting fluid in chamber I9 to flow to chamber 2 I, thereby increasing fluid pressure in chamber 2|, raising piston 3| away from valve 29, and permitting fluid to escape as aforesaid. Such reduction of fluid pressure in chamber 2| will cause full downward movement of piston 46, thereby causing a rapid rise in fluid pressure in chamber 2| and immediate rapid raising of piston 3| and discharge of fluid from chamber I9. An increase of fluid pressure in chamber 2| and below piston 46, above the fluid pressure in chamber I9, causes full upward travel of piston 46, full opening of Valve 5|, and direct communication between a source of fluid pressure at opening 23 and chamber I9, until fluid pressure in chamber I9 and above piston 46 is raised sufliciently to move piston 46 downwardly against fluid pressure established in chamber 2 I, and promptly close valve 5I against further flow of fluid from chamber 24.

Maximum pressure on spring 38 is applied to piston 3| when in running position. When a brake application is made, handle 39 is moved, thus reducing spring pressure on piston 3|, permitting upward travel thereof due to train-line pressure in the control chamber. This opens seat 39 and exhausts control pressure through exhaust port 22. Pressure in chamber I9, being in excess of pressure in chamber 2 I moves piston 46 downwardly, thus venting train-line pressure into chamber 2| This increase in pressure in charnber .2|, acting against reduced spring pressure,

permits Strain-.line air to exhaust until Vtrain-line pressure equalizes with .reduced spring pressure. Valve seats t52 :and `28 'remain closed, yof course, 'during reduction.

Release of Vbrakes is eifected byrreturn of handle 39 -to running position. The reduced pressure in control'charnber 2! required for 'brake application is insufcient to'oppose downward'movement of piston 3S! which is now actuated by Afullspring pressure. The excess oi spring pressure causes :double-seated valve 26 to move downwardly, opening seat '2l and admitting-reservoir-air into control chamber 2i -until `pressure therein equals spring pressure, which, for instance, may be '70 pounds. Pressure in chamber I9 is still reduced, yand the 4pressure in chamber 2 i ,being higher, acts against .the undersurface of piston 46, moving it upwardly, Y-closing `floating seat 68 and opening .xed seat '52 of valve 50. .Since seat 52 is now full open, reservvoir air travels into chamber I 9 and the train line. When pressures in chambers I9 and 2| equalize, piston 4S moves down and closes seat 52. The valves Aare now Yin lap position.

It will be apparent that any movement of handle 39 will-effect a change in the downward presf sure of yspring 38, and that such pressure change will be reflected in 'chamber 2l and in chamber 'I5-9. Thus, Vpressure in any means communicating with chamber 'l 9 Ycan be graduated up or down at rthe 'will of the operator by setting handle 39 in the corresponding position, and the desired pressure will `be maintained at the means com- .municating with chamber I9 up to the limit of Athe source of iiuid pressure at inlet 23.

While one form or embodiment of the inven- -tion has vbeen shown and described herein for outlet port, an exhaust port, and a control cham- ,i

ber, a double-seated valve provided with a first seat forming a closure between said inlet and outlet ports, a'second seat forming a closure between '.the outlet port and the control chamber, ra fluid pressure actuated element positioned ibetween said outlet port and said control chamber for controlling movement of the double-seated valve, the 'housing having an opening between the `inlet port and the control chamber, and a manually controllable valve for closing such opening and for exhausting fluid from 'the 'control chamber. l

2. In a uid pressure control valve, .the combination of a housing having an inlet port, an outlet port, and a control chamber, a doubleseated Valve provided with arst valve member forming a closure between said inlet andoutlet ports, a Asecond valve member forming -a -closure between the outlet port and the ycontrol chamber, a fluid pressure actuated element positioned ybetween said outlet port and said control chamber for controlling movement of the double-seated valve, means for controlling fluid pressure insaid control chamber, said means comprising a valve .having a seat :providing .an yopening between the ,inlet port :and -the control chamber, and man- .ment positioned fbietween said outlet port and said control chamber for controlling movement ofthe double-seated valve, and means for controlling fluid pressure in said control chamber, said 'means Vcomprising a `second fluid pressure `actuated element positioned between said control Vchamber and said exhaust port and being provided with a valve seat communicating with said exhaust port, .one surface of said second fluid pressure-actuated lelement being subject to Iiluid ,pressure in said control chamber, a second double-seated valve provided with a rst valve vmember forming ra closure between said inlet port and said control chamber, a second valve member adapted to engage said valve seat on said latter fluid .pressure actuated element, and resilient compressible vmeans engaging said fluid 4pressure actuated 4element to yoppose movement thereof dueto fluid pressure in said control chamber.

4. In aviiuid pressure control valve, the combination 'of a housing having an inlet port, an outlet port,-a control chamber, and an exhaust port, a iluid `pressure actuated element posi- `tioned between said vcontrol 'chamber and said exhaust port Vand being provided with a valve seat communicating with'said exhaust port, one surface -of said uid pressure actuated element being subject to Viluid pressure in said control fchamber, 'afdouble-seated valve provided with a .first valve member forming a closure between .said -inlet Aand outlet ports, and a second valve member adapted to engage said valve seat on said fluid vpressure actuated element, resilient compressible means engaging .said fluid pressure actuated element :to oppose movement thereof due 'to fluid Ypressure in said control chamber, a ysecond double-seated `valve provided with a first `valve member forming a closure between said -inlet and outlet ports, and a second valve member forming a vclosure between the outlet port and the control chamber, a second fluid pressure actuated 'element positioned between said outlet port and said control chamber for controlling movement 'of the latter valve, said latter fluid pressure :actuated element having an opening therein Iproviding va iloating seat for the second v valve member Yof the second double-seated valve.

5. 'In a fluid pressure control valve, the com- .bination of 1a `'housing having an inlet chamber, an rout-'let chamber, a control chamber, and an opening between vsaid inlet and outlet chambers, a valve hadapted, to .close said opening, a fluid pressure actuated element positioned between said outlet chamber said control chamber and subject to fluid 'pressure in each said cham- Iberysaid fluid pressure actuated element being adapted `to actuate said valve, and a restricted port between said outlet chamber and said control chamber.

f6. :In a fluid pressure control valve, the cornvbination ,of 'a housing provided with an inlet chamber, fan outlet chamber, and rmeans toeffect unrestricted v'opening therebetween, said means comprising a valve element positioned between said inlet and outlet chambers, fluid pressure actuated means for actuating said valve element, such fluid pressure actuated means being subject to fluid pressure in said outlet chamber on one side thereof and subject to controlled fluid pressure on its opposite side, whereby said valve element is full open when said controlled fluid pressure exceeds said outlet chamber fluid pressure, and whereby said valve element is full closed when said outlet chamber fluid pressure is not less than said controlled fluid pressure, and selflapping means for controlling said latter fluid pressure.

7. In a fluid pressure control valve, the combination of a housing provided with an inlet chamber, an outlet chamber, means to effect an un- -restricted opening therebetween, and means to effect a restricted opening therebetween, said former means comprising a valve element positioned between said inlet and outlet chambers, fluid pressure actuated means for actuating said valve element, such fluid pressure actuated means having two opposite surfaces of substantially equal areas and being subject to fluid pressure in said outlet chamber over one such entire surface, and subject to controlled fluid pressure over the second entire surface, whereby said valve element is full open when said controlled fluid pressure substantially exceeds said outlet chamber fluid pressure, and whereby said valve element is full closed when said outlet chamber fluid pressure is not less than said controlled fluid pressure, and means for controlling said latter fluid pressure.

y8. In a fluid pressure control valve, the ccmbinaton of a housing provided with an inlet chamber, an outlet chamber, means to effect unrestricted opening therebetween, said means comprising a Valve element positioned between said inlet and outlet chambers, fluid pressure actuated means to actuate said Valve element, said fluid pressure actuated means having two oppo- 4site surfaces of substantially equal areas and being subject to fluid pressure in said outlet chamber over one such entire surface, and subject to controlled fluid pressure over the second entire surface, whereby said valve element is full open when said controlled fluid pressure exceeds said outlet chamber fluid pressure, and whereby said valve element is full closed when said outlet chamber pressure is not less than said controlled fluid pressure, said latter fluid pressure being controlled by self-lapping means comprising adouble-seated Valve having a ilrst seat adapted to provide communication between said inlet chamber and controlled fluid pressure side of aforesaid fluid pressure actuated means, and a second seat adapted to provide communication between controlled fluid pressure side of aforesaid fluid pressure actuated means and exhaust, a second fluid pressure actuated means to actuate said double-seated valve, such latter second fluid pressure actuated means being subject to said controlled fluid pressure on one side thereof and subject to controllable, resiliently compressible means on its :opposite side.

9. In a fluid pressure control valve, the combination of a housing having an inlet chamber, an outlet chamber and a control chamber, means to effect unrestricted opening between said inlet and outlet chambers, said means comprising a valve element positioned between said inlet and outlet chambers, fluid pressure actuated means to actuate said valve element, such fluid pressure actuated means having two opposite surfaces of substantially equal areas and being subject to fluid pressure in said outlet chamber over one such entire surface, and subject to controlled fluid pressure over the second entire surface, whereby said valve element is full open when said control chamber fluid pressure substantially exceeds said outlet chamber fluid pressure, and whereby said valve element is full closed when said outlet chamber fluid pressure is substantially not less than said control chamber fluid pressure, a restricted port between said control chamber and Said outlet chamber, and self-lapping means for controlling fluid pressure in said control chamber.

10. In a fluid pressure control valve, the combination of a housing having an inlet chamber, an outlet chamber, and a control chamber, means to effect unrestricted opening between said inlet and outlet chambers, said means comprising a valve element positioned between said inlet and outlet chambers, fluid pressure actuated means to actuate said valve element, said fluid pressure actuated means having two opposite surfaces of substantially equal areas and being subject to fluid pressure in said outlet chamber over one such entire surface, and subject to controlled fluid pressure over the second entire surface, whereby said valve element is full open when said control chamber fluid pressure exceeds said outlet chamber fluid pressure, and whereby said valve element is full closed when said outlet chamber fluid pressure is not less than said control chamber fluid pressure, asecond valve element associated withthe aforesaid Valve element and associated with a seat on aforesaid fluid pressure actuated means, whereby said seat is opened by movement of said fluid pressure actuated means when said outlet chamber fluid pressure exceeds said control chamber fluid pressure, thereby establishing communication between said outlet and control chambers, and means for controlling fluid pressure in said control chamber.

11. In a fluid pressure control valve structure, the combination of a housing having an inlet chamber, an outlet chamber, a control chamber, and an exhaust port, means to effect unrestricted yopening between said inlet and outlet chambers, said means comprising a valve element positioned between said inlet and outlet chambers, fluid pressure actuated means to actuate said valve element, such fluid pressure actuated means having two opposite surfaces of substantially equal areas and being subject to fluid pressure in said outlet chamber over -one such entire surface, and ysubject to controlled fluid pressure over the second entire surface, whereby said valve element is full open when said control chamber fluid pressure substantially exceeds said outlet chamber fluid pressure, and whereby said valve element is full closed when said outlet chamber fluid pressure is not less than said control chamber fluid pressure, a second valve element associated with and aforesaid exhaust port, a second fluid pressure actuated means carrying said second seat, said second fluid pressure actuated means having one surface subject to uid pressure in said control chamber, said fluid pressure being opposed by resiliently controllable means, whereby increase of pressure on said resiliently controllable means opens said first seat to admit fluid under pressure from ysaid inlet chamber to said control chamber, and whereby decrease of pressure on said resiliently controllable means permits said first seat to close and opens said second seat to exhaust fluid under pressure from said control chamber to aforesaid exhaust port.

12. A structure as described in claim 11, with a restricted port between said control chamber and said outlet chamber.

13. In a uid pressure control valve, the combination of a housing provided with an inlet chamber, an -outlet chamber, and means to effect unrestricted opening therebetween, said means comprising a Valve element positioned between said inlet and outlet chambers, fluid pressure actuated means for actuating said valve element, such fluid pressure actuated means being subject to fluid pressure in said outlet chamber on one side thereof and subject to controlled fluid pressure on its opposite side, whereby said valve element is full open when said controlled fluid pressure exceeds said outlet chamber fluid pressure, and whereby said valve element is full closed when said outlet chamber fluid pressure is not less than said controlled fluid pressure, and

Number means for controlling said latter fluid pressure.

14. In a fluid pressure control valve, the combinaton of a housing having an inlet chamber, an outlet chamber and a control chamber, means to effect unrestricted opening between said inlet and outlet chambers, said means comprising a valve element positioned between said inlet and outlet chambers, fluid pressure actuated means to actuate said valve element, such fluid pressure actuated means being subject t-o fluid pressure in said outlet chamber on one side thereof and subject to fluid pressure in said control chamber on its opposite side, whereby said Valve element is full open when said control chamber fluid pressure substantially exceeds said outlet chamber fluid pressure, and whereby said valve element is full closed when said outlet chamber fluid pressure is substantially not less than said control chamber uid pressure, a restricted port between said control chamber and said outlet chamber, and means for controlling fluid pressure in said control chamber.

JOHN W. MARSH.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Name Date '792,152 McElroy June 13, 1905 

